/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using System.Collections;
using System.Globalization;
using System.Text;
using PdfSharp.Drawing;
using System.IO;
using PdfSharp.Internal;
using PdfSharp.Pdf.Security;

namespace PdfSharp.Pdf.Internal
{
  /// <summary>
  /// Groups a set of static encoding helper functions.
  /// </summary>
  internal class PdfEncoders
  {
    PdfEncoders()
    { }

    const char InvalidChar = '?';

    //[Obsolete]
    //public static void WriteAnsi(Stream stream, string text)
    //{
    //  stream.Write(PdfEncoders.WinAnsiEncoding.GetBytes(text), 0, text.Length);
    //}

    /// <summary>
    /// Gets the raw encoding.
    /// </summary>
    public static Encoding RawEncoding
    {
      get
      {
        if (PdfEncoders.rawEncoding == null)
          PdfEncoders.rawEncoding = new PdfSharp.Pdf.Internal.RawEncoding();
        return PdfEncoders.rawEncoding;
      }
    }
    static Encoding rawEncoding;

    /// <summary>
    /// Gets the raw Unicode encoding.
    /// </summary>
    public static Encoding RawUnicodeEncoding
    {
      get
      {
        if (PdfEncoders.rawUnicodeEncoding == null)
          PdfEncoders.rawUnicodeEncoding = new PdfSharp.Pdf.Internal.RawUnicodeEncoding();
        return PdfEncoders.rawUnicodeEncoding;
      }
    }
    static Encoding rawUnicodeEncoding;

    /// <summary>
    /// Gets the Windows 1252 (ANSI) encoding.
    /// </summary>
    public static Encoding WinAnsiEncoding
    {
      get
      {
          if (PdfEncoders.winAnsiEncoding == null)
              ///PdfEncoders.winAnsiEncoding = Encoding.GetEncoding("1252");
              PdfEncoders.winAnsiEncoding = new  ASCIIEncoding();
        return PdfEncoders.winAnsiEncoding;
      }
    }
    static Encoding winAnsiEncoding;

    /// <summary>
    /// Gets the PDF DocEncoding encoding.
    /// </summary>
    public static Encoding DocEncoding
    {
      get
      {
        if (PdfEncoders.docEncoding == null)
          PdfEncoders.docEncoding = new PdfSharp.Pdf.Internal.DocEncoding();
        return PdfEncoders.docEncoding;
      }
    }
    static Encoding docEncoding;

    /// <summary>
    /// Gets the UNICODE little-endian encoding.
    /// </summary>
    public static Encoding UnicodeEncoding
    {
      get
      {
        if (PdfEncoders.unicodeEncoding == null)
          PdfEncoders.unicodeEncoding = Encoding.Unicode;
        return PdfEncoders.unicodeEncoding;
      }
    }
    static Encoding unicodeEncoding;

    ///// <summary>
    ///// Encodes a string from a byte array. Each character gets the code of the corresponding byte.
    ///// </summary>
    //public static string RawString(byte[] bytes, int offset, int length)
    //{
    //  char[] chars = new char[length];
    //  for (int idx = offset, ch = 0; idx < offset +  length; idx++, ch++)
    //    chars[ch] = (char)bytes[idx];
    //  return new string(chars, 0, length);
    //}
    //
    //public static string RawString(byte[] bytes)
    //{
    //  return RawString(bytes, 0, bytes.Length);
    //}

#if false
    public static string EncodeAsLiteral(string text, bool unicode)
    {
      if (text == null || text == "")
        return "_";

      StringBuilder pdf = new StringBuilder("");
      if (!unicode)
      {
        byte[] bytes = WinAnsiEncoding.GetBytes(text);
        int count = bytes.Length;
        pdf.Append("(");
        for (int idx = 0; idx < count; idx++)
        {
          char ch = (char)bytes[idx];
          if (ch < 32)
          {
            switch (ch)
            {
              case '\n':
                pdf.Append("\\n");
                break;

              case '\r':
                pdf.Append("\\r");
                break;

              case '\t':
                pdf.Append("\\t");
                break;

              case '\f':
                pdf.Append("\\f");
                break;

              default: 
                pdf.Append(PdfEncoders.InvalidChar); // TODO
                break;
            }
          }
          else
          {
            switch (ch)
            {
              case '(':
                pdf.Append("\\(");
                break;

              case ')':
                pdf.Append("\\)");
                break;

              case '\\':
                pdf.Append("\\\\");
                break;

              default:
                pdf.Append(ch);
                break;
            }
          }
        }
        pdf.Append(')');
      }
      else
      {
        pdf.Append("<");
        byte[] bytes = UnicodeEncoding.GetBytes(text);
        int count = bytes.Length;
        for (int idx = 0; idx < count; idx += 2)
        {
          pdf.AppendFormat("{0:X2}{1:X2}", bytes[idx + 1], bytes[idx]);
          if (idx != 0 && (idx % 48) == 0)
            pdf.Append("\n");
        }
        pdf.Append(">");
      }
      return pdf.ToString();
    }
#endif

    //public static string EncodeAsLiteral(string text)
    //{
    //  return EncodeAsLiteral(text, false);
    //}

    /// <summary>
    /// Converts a raw string into a raw string literal, possibly encrypted.
    /// </summary>
    public static string ToStringLiteral(string text, PdfStringEncoding encoding, PdfStandardSecurityHandler securityHandler)
    {
      if (text == null || text == "")
        return "()";

      byte[] bytes;
      switch (encoding)
      {
        case PdfStringEncoding.RawEncoding:
          bytes = PdfEncoders.RawEncoding.GetBytes(text);
          break;

        case PdfStringEncoding.WinAnsiEncoding:
          bytes = PdfEncoders.WinAnsiEncoding.GetBytes(text);
          break;

        case PdfStringEncoding.PDFDocEncoding:
          bytes = PdfEncoders.DocEncoding.GetBytes(text);
          break;

        case PdfStringEncoding.Unicode:
          bytes = PdfEncoders.UnicodeEncoding.GetBytes(text);
          break;

        default:
          throw new NotImplementedException(encoding.ToString());
      }
      return PdfEncoders.RawEncoding.GetString(FormatStringLiteral(bytes, encoding == PdfStringEncoding.Unicode, true,
        false, securityHandler));
    }

    /// <summary>
    /// Converts a raw string into a raw string literal, possibly encrypted.
    /// </summary>
    public static string ToStringLiteral(byte[] bytes, bool unicode, PdfStandardSecurityHandler securityHandler)
    {
      if (bytes == null || bytes.Length == 0)
        return "()";

      return PdfEncoders.RawEncoding.GetString(FormatStringLiteral(bytes, unicode, true, false, securityHandler));
    }

    /// <summary>
    /// Converts a raw string into a raw hexadecimal string literal, possibly encrypted.
    /// </summary>
    public static string ToHexStringLiteral(string text, PdfStringEncoding encoding, PdfStandardSecurityHandler securityHandler)
    {
      if (text == null || text == "")
        return "_";

      byte[] bytes;
      switch (encoding)
      {
        case PdfStringEncoding.RawEncoding:
          bytes = PdfEncoders.RawEncoding.GetBytes(text);
          break;

        case PdfStringEncoding.WinAnsiEncoding:
          bytes = PdfEncoders.WinAnsiEncoding.GetBytes(text);
          break;

        case PdfStringEncoding.PDFDocEncoding:
          bytes = PdfEncoders.DocEncoding.GetBytes(text);
          break;

        case PdfStringEncoding.Unicode:
          bytes = PdfEncoders.UnicodeEncoding.GetBytes(text);
          break;

        default:
          throw new NotImplementedException(encoding.ToString());
      }
      return PdfEncoders.RawEncoding.GetString(FormatStringLiteral(bytes, encoding == PdfStringEncoding.Unicode, true,
        true, securityHandler));
    }

    /// <summary>
    /// Converts a raw string into a raw hexadecimal string literal, possibly encrypted.
    /// </summary>
    public static string ToHexStringLiteral(byte[] bytes, bool unicode, PdfStandardSecurityHandler securityHandler)
    {
      if (bytes == null || bytes.Length == 0)
        return "_";

      return PdfEncoders.RawEncoding.GetString(FormatStringLiteral(bytes, unicode, true, true, securityHandler));
    }

    /// <summary>
    /// Converts the specified byte array into a byte array representing a string literal.
    /// </summary>
    /// <param name="bytes">The bytes of the string.</param>
    /// <param name="unicode">Indicates whether one or two bytes are one character.</param>
    /// <param name="prefix">Indicates whether to use Unicode prefix.</param>
    /// <param name="hex">Indicates whether to create a hexadecimal string literal.</param>
    /// <param name="securityHandler">Encrypts the bytes if specified.</param>
    /// <returns>The PDF bytes.</returns>
    public static byte[] FormatStringLiteral(byte[] bytes, bool unicode, bool prefix, bool hex, PdfStandardSecurityHandler securityHandler)
    {
      if (bytes == null || bytes.Length == 0)
        return hex ? new byte[] { (byte)'<', (byte)'>' } : new byte[] { (byte)'(', (byte)')' };

      Debug.Assert(!unicode || bytes.Length % 2 == 0, "Odd number of bytes in Unicode string.");

      bool encrypted = false;
      if (securityHandler != null)
      {
        bytes = (byte[])bytes.Clone();
        bytes = securityHandler.EncryptBytes(bytes);
        encrypted = true;
      }

      int count = bytes.Length;
      StringBuilder pdf = new StringBuilder();
      if (!unicode)
      {
        if (!hex)
        {
          pdf.Append("(");
          for (int idx = 0; idx < count; idx++)
          {
            char ch = (char)bytes[idx];
            if (ch < 32)
            {
              switch (ch)
              {
                case '\n':
                  pdf.Append("\\n");
                  break;

                case '\r':
                  pdf.Append("\\r");
                  break;

                case '\t':
                  pdf.Append("\\t");
                  break;

                case '\b':
                  pdf.Append("\\b");
                  break;

                // currups encrypted text                    
                //case '\f':
                //  pdf.Append("\\f");
                //  break;

                default:
                  // Don't escape chararchters less than 32 if the string is encrypted, because it is
                  // unreadable anyway.
                  encrypted = true;
                  if (!encrypted)
                  {
                    pdf.Append("\\0");
                    pdf.Append((char)(ch % 8 + '0'));
                    pdf.Append((char)(ch / 8 + '0'));
                  }
                  else
                    pdf.Append(ch);
                  break;
              }
            }
            else
            {
              switch (ch)
              {
                case '(':
                  pdf.Append("\\(");
                  break;

                case ')':
                  pdf.Append("\\)");
                  break;

                case '\\':
                  pdf.Append("\\\\");
                  break;

                default:
                  pdf.Append(ch);
                  break;
              }
            }
          }
          pdf.Append(')');
        }
        else
        {
          pdf.Append('<');
          for (int idx = 0; idx < count; idx++)
            pdf.AppendFormat("{0:X2}", bytes[idx]);
          pdf.Append('>');
        }
      }
      else
      {
      Hex:
        if (hex)
        {
          if (prefix)
            pdf.Append("<FEFF");
          else
            pdf.Append("<");
          for (int idx = 0; idx < count; idx += 2)
          {
            pdf.AppendFormat("{0:X2}{1:X2}", bytes[idx], bytes[idx + 1]);
            if (idx != 0 && (idx % 48) == 0)
              pdf.Append("\n");
          }
          pdf.Append(">");
        }
        else
        {
          // TODO non hex literals... not sure how to treat linefeeds, '(', '\' etc.
          hex = true;
          goto Hex;
        }
      }
      return PdfEncoders.RawEncoding.GetBytes(pdf.ToString());
    }

    /// <summary>
    /// Converts WinAnsi to DocEncode characters. Incomplete, just maps � and some other characters.
    /// </summary>
    static byte[] docencode_______ = new byte[256]
    {
      // TODO: 
      0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
      0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
      0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
      0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
      0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
      0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
      0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
      0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
      0xA0, 0x7F, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
      0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x8A, 0x8C, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
      0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
      0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
      0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
      0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
      0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF,
      0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF,
    };

    //public static string DocEncode(string text, bool unicode)//, PdfStandardSecurityHandler securityHandler)
    //{
    //  if (text == null || text == "")
    //    return "()";
    //
    //  int length = text.Length;
    //  StringBuilder encoded = new StringBuilder(2 * length);
    //  if (!unicode)
    //  {
    //    byte[] bytes = PdfEncoders.WinAnsiEncoding.GetBytes(text);
    //    encoded.Append('(');
    //    for (int idx = 0; idx < length; idx++)
    //    {
    //      char ch = (char)bytes[idx];
    //      if (ch > 255)
    //      {
    //        //TODO unicode?
    //        encoded.Append(PdfEncoders.InvalidChar);
    //        //encoded.Append(ch);
    //        continue;
    //      }
    //      ch = (char)docencode[(int)ch];
    //      if (ch < 32)
    //      {
    //        switch (ch)
    //        {
    //          case '\n':
    //            encoded.Append("\\n");
    //            break;
    //
    //          case '\r':
    //            encoded.Append("\\r");
    //            break;
    //
    //          case '\t':
    //            encoded.Append("\\t");
    //            break;
    //
    //          case '\f':
    //            encoded.Append("\\f");
    //            break;
    //
    //          default: 
    //            encoded.Append(PdfEncoders.InvalidChar); // TODO
    //            break;
    //        }
    //      }
    //      else
    //      {
    //        switch (ch)
    //        {
    //          case '(':
    //            encoded.Append("\\(");
    //            break;
    //
    //          case ')':
    //            encoded.Append("\\)");
    //            break;
    //
    //          case '\\':
    //            encoded.Append("\\\\");
    //            break;
    //
    //          default:
    //            encoded.Append(ch);
    //            break;
    //        }
    //      }
    //    }
    //    encoded.Append(')');
    //  }
    //  else
    //  {
    //    encoded.Append("<FEFF");
    //    for (int idx = 0; idx < length; idx++)
    //      encoded.AppendFormat("{0:X4}", (int)text[idx]);
    //    encoded.Append('>');
    //  }
    //  return encoded.ToString();
    //}

    //public static string DocEncode(string text)
    //{
    //  return DocEncode(text, false);
    //}

    ///// <summary>
    ///// Encodes a hexadecimal doc-encoded string literal.
    ///// </summary>
    //public static string DocEncodeHex(string text, bool unicode)
    //{
    //  if (text == null || text == "")
    //    return "_";
    //
    //  int length = text.Length;
    //  StringBuilder encoded = new StringBuilder(3 * length);
    //  if (!unicode)
    //  {
    //    byte[] bytes = PdfEncoders.WinAnsiEncoding.GetBytes(text);
    //    encoded.Append('<');
    //    for (int idx = 0; idx < length; idx++)
    //      encoded.AppendFormat("{0:X2}", docencode[bytes[idx]]);
    //    encoded.Append('>');
    //  }
    //  else
    //  {
    //    encoded.Append("<FEFF");
    //    for (int idx = 0; idx < length; idx++)
    //    {
    //      encoded.AppendFormat("{0:X4}", (int)text[idx]);
    //    }
    //    encoded.Append('>');
    //  }
    //  return encoded.ToString();
    //}

    //public static string DocEncodeHex(string text)
    //{
    //  return DocEncodeHex(text, false);
    //}

    /// <summary>
    /// ...because I always forget CultureInfo.InvariantCulture and wonder why Arcobat
    /// cannot understand my German decimal separator...
    /// </summary>
    public static string Format(string format, params object[] args)
    {
      return String.Format(CultureInfo.InvariantCulture, format, args);
    }

    /// <summary>
    /// Converts a float into a string with up to 3 decimal digits and a decimal point.
    /// </summary>
    public static string ToString(double val)
    {
      return val.ToString("0.###", CultureInfo.InvariantCulture);
    }

    /// <summary>
    /// Converts an XColor into a string with up to 3 decimal digits and a decimal point.
    /// </summary>
    public static string ToString(XColor color, PdfColorMode colorMode)
    {
      // If not defined let color decide
      if (colorMode == PdfColorMode.Undefined)
      {
        if (color.ColorSpace == XColorSpace.Cmyk)
          colorMode = PdfColorMode.Cmyk;
        else
          colorMode = PdfColorMode.Rgb;
      }
      switch (colorMode)
      {
        case PdfColorMode.Cmyk:
          return String.Format(CultureInfo.InvariantCulture, "{0:0.###} {1:0.###} {2:0.###} {3:0.###}",
            color.C, color.M, color.Y, color.K);

        default:
          return String.Format(CultureInfo.InvariantCulture, "{0:0.###} {1:0.###} {2:0.###}",
            color.R / 255.0, color.G / 255.0, color.B / 255.0);
      }
    }

    /// <summary>
    /// Converts an XMatrix into a string with up to 3 decimal digits and a decimal point.
    /// </summary>
    public static string ToString(XMatrix matrix)
    {
      return String.Format(CultureInfo.InvariantCulture,
        "{0:0.###} {1:0.###} {2:0.###} {3:0.###} {4:0.###} {5:0.###}",
        matrix.M11, matrix.M12, matrix.M21, matrix.M22, matrix.OffsetX, matrix.OffsetY);
    }
  }
}
